Can I modify a magazine for hunting?

In my state, I have to have a 5 round or less magazine when deer hunting with a rifle. Do you think it would pass muster to put a thin block of wood vertically inside a polymer 30rd mag within the spring and beneath the follower? If we're allowed to simply put a dowel into our shotgun magazine to limit its capacity for waterfowl hunting, can we do something similar to a polymer mag on an AR platform?
I realize that 5 rd mags are available for the AR; I'd just rather not buy one.
Also, this question does not address the suitability of .223 on whitetail... I see that that question has been, um, addressed, before.

Thank you Gentlemen for your answers.
Primalmu, what I got from your recommendation, other than to plumb the depths of my skin-flintery, was that this is actually done. When you say "mag to block", it sounds like I didn't invent this idea.

I went threw this last year, alot of the 5 rounders are CHEAP and less reliable, I bought one of these John Masen ones and I had to mod it just to get it to fit in the gun than I had to shorten the follower cus it would only hold 4 rounds. I didnt get it at CTD i paid 25 for it at a gunshow :banghead:
you can get kits to make 10 rounders in to 5ers from midway I think.
This fall I got and Enfield #5 and decided I wanted to hunt whitetail with it, so I just made a wooden block about 4 1/2 303's deep and installed it under the follower, kinda like blocking your tube mag for duck hunten

I understand not wanting to spend the money on a 5 rounder but that $20 might seam pretty cheap if the game warden manages to stuff a sixth round in the mag. the loss of an ar + the fine will make a $20 mag seam cheap.

I understand not wanting to spend the money on a 5 rounder but that $20 might seam pretty cheap if the game warden manages to stuff a sixth round in the mag. the loss of an ar + the fine will make a $20 mag seam cheap.

Click to expand...

And make sure you don't have any full capacity mags on you or in your vehicle....

Yeah Id be going with the smallest available. With a blocked hi cap magazine your opening yourself up for inspection/chat with a Game Warden.. While you maybe 100% legit it still might be an inconvenience or crappy timing when he/she wants to come speak to you.

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